More U.S. flights cancelled in wake of Microsoft-CrowdStrike global cyber outage

More than 1,200 flights have been cancelled within, into or out of the U.S. on Sunday, after the Microsoft and CrowdStrike outage.

More than 1,200 flights have been canceled within, into or out of the U.S. on Sunday, led by cancellations in top carriers Delta Air Lines and United Airlines, according to data tracker FlightAware.com, in the wake of Friday's global cyber outage.

Airlines are struggling to recover from the tech outage that forced multiple carriers to ground flights on Friday.

Delta Chief Executive Ed Bastian said in a company release Sunday that flight cancellations continue on Sunday as the airline works to restore operation following the technology issue.

The pause in Delta's operation resulted in more than 3,500 Delta and Delta Connection flights cancelled through Saturday, according to the release. Delta also said it had extended a travel waiver for all customers booked from July 19-21.

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CNBC reported Sunday that Delta was offering its crews extra pay to staff flights as it recovers from the outage.

United on Sunday said it had no further comment following an update on Saturday. It had said that most of its technology systems have been restored, but that it will continue to see cancellations and delays this weekend. It also said it had extended a travel waiver through Sunday for customers.